A worldwide network of Argo floats gives scientists an unprecedented understanding of the ocean depths. Argo floats descend and ascend through the top 2,000 meters of the ocean, collecting observations as they move.

We're nine laps into the race to set a new global annual temperature record. NOAA climate scientist Deke Arndt talks about how this year's race might end--and why yearly rankings tell us less about the big picture of climate change than we might think.

NOAA’s National Climatic Data Center announced that last month was the warmest September on record for the planet. If the surface temperature remains elevated at the same level for the remainder of the year, 2014 will set a new record for the warmest annual average temperature since records began in 1880.

Alaska’s coastal waters are especially vulnerable to the drop in pH—acidification—that comes when excess carbon dioxide dissolves into the ocean from the atmosphere. These maps show relative risk levels for commerical and subsistence fisheries.

As sea level has changed, so has the way we measure it. Here’s a look at some of the technologies climate and marine scientists have used to track Earth’s tides and global sea level over the past two centuries.

Across the globe, changes in salinity over time generally match changes in precipitation: places where rainfall declines become saltier, while places where rainfall increases become fresher. Where did saltiness change over the past decade?